#17414C

CSS

:root {
  --cold-and-dark: #17414c;
  --cold-and-dark-rgb: 23 65 76;
  --cold-and-dark-oklch: oklch(0.351 0.05 218);
}

.element {
  color: var(--cold-and-dark);
  background-color: hsl(192 54% 19%);
  border-color: oklch(0.351 0.05 218);
}

Tailwind CSS v4

@theme {
  --color-cold-and-dark: #17414c;
  --color-cold-and-dark-50: #e6f9ff;
  --color-cold-and-dark-100: #d7ecf3;
  --color-cold-and-dark-200: #bedae3;
  --color-cold-and-dark-300: #9cbec9;
  --color-cold-and-dark-400: #7ea6b2;
  --color-cold-and-dark-500: #608f9c;
  --color-cold-and-dark-600: #517984;
  --color-cold-and-dark-700: #41616a;
  --color-cold-and-dark-800: #2e474d;
  --color-cold-and-dark-900: #1f3136;
  --color-cold-and-dark-950: #0f1d21;
}

SCSS

$cold-and-dark: #17414c;
$cold-and-dark-rgb: 23, 65, 76;
$cold-and-dark-light: mix(#fff, $cold-and-dark, 20%);
$cold-and-dark-dark: mix(#000, $cold-and-dark, 20%);

.element {
  color: $cold-and-dark;
  box-shadow: 0 0 0 2px rgba($cold-and-dark, 0.35);
}